Final answer:
The pregnant woman with a balanced diet and regular prenatal care has the lowest risk of becoming inadequately nourished due to her active health monitoring and nutritional intake.
Step-by-step explanation:
Among the individuals listed, Option 2: A pregnant woman with a balanced diet and regular prenatal care has the lowest risk of becoming inadequately nourished. This is because a balanced diet and regular prenatal care suggest that she is monitoring her nutritional intake and overall health, which is particularly important during pregnancy.
The older adult with a BMI of 18.5 kg/m² (Option 1) is considered to have a normal weight but is at the lower threshold, which may predispose to undernutrition if not carefully managed. The vegetarian athlete (Option 3) is likely to be adequately nourished if their diet is well-planned. However, athletes have higher energy demands and may be at risk if caloric and protein intake aren't sufficient. The sedentary young adult with a BMI of 30 kg/m² (Option 4) is considered obese and may have a diet that is high in calories but low in nutritional value, thereby increasing the risk of being malnourished despite a higher body weight.